Obstructive Sleep Apnoea (OSA) is a disease whereby the upper airway is obstructed many times per night to such an extent that the patient is unable to breathe (apnoea) or has a reduced breathing capacity (hyponea). Diagnosis of OSA can be done in a sleep lab by monitoring a patient during an overnight measurement. If the total of number of apnoea's and hyponeas exceeds a certain limit, the OSA diagnosis is assigned.
Jung et al disclose that predictive indicators of OSA are the anatomical features related to the upper airway in Predictive value of Kushida index and use acoustic pharyngometry for the evaluation of upper airway in subjects with or without obstructive sleep apnoea. (J Korean Med Sci, 2004. 19(5): p. 662-7). Jung et al also disclose that the spectral characteristics of speech, notably vowels, depend on the anatomical dimensions of the throat. As a result of the latter, spectral characteristics of speech can be used as indicators for OSA. For this an acoustic pharyngometer can be used to actively extract geometric parameters of the upper airway by sending an acoustic signal into the throat and processing the reflections of the latter. However, test/retest validity and the accuracy of an acoustic pharyngometry measurement performed by devices known in the art is not that high.
CA2585824 discloses a method for screening OSA, namely to derive flow information from breathing sounds in the ear, and combine them with the level of snoring. However, the method disclosed in CA '824 can only be used to detect apnoea as they happen.
In addition, unfortunately these diagnosis tools for OSA common in the art are used in a sleep lab, which is expensive, time-consuming and uncomfortable for the patient. Furthermore, the methods at present used for screening OSA are very tedious and labour-intensive.
Therefore a need still exists for an improved and less time-consuming test for daytime investigating and screening of OSA in a short and convenient way.